Deposition of materials (wire, powder, or strip) using lasers is inherently a process that produces low-tolerance features, or it may be intentionally low tolerance to increase throughput or deposition rate at the cost of feature resolution. To further refine a low tolerance finish or develop other desired features, further processing of artifacts left over from a previous additive process is sometimes performed during subsequent removal, smoothing, refining, ablation, or machining operations. Such subsequent processing operations have sometimes used a separate machine to perform material removal by methods involving mechanical post-processing, chemical treatment, or thermal treatment (e.g., by application of heat). Separate machines for such operations can add, among other things, production delay, tooling cost, and training burden.
Patent Application Pub. No. US 2009/0283501 A1 of Erikson et al. describes a laser deposition apparatus for preheating a workpiece prior to deposition. The cross-sectional width of a beam is increased and decreased for, respectively, preheating and deposition by moving optical components housed in a deposition nozzle—close to the operating environment and potentially susceptible to debris, among other deficiencies.